The disclosure relates generally to combustion systems, and more particularly, to a combustor cap with a cooling passage therein, a combustion system employing the combustor cap and an additive manufacturing file of the combustor cap.
Combustion systems such as used in a gas turbine engine include a number of fuel nozzles adjacent to a combustor chamber. A combustor cap is a plate-like member that includes a plurality of large holes to create a barrier between a nozzle area and/or position the fuel nozzles in a spaced relationship relative to the combustor chamber. Inside the combustor chamber, fuel from the fuel nozzles is mixed with air from the compressor and combusted in order to turn a turbine engine. Combustor caps are exposed to the combustion gases within the combustor chamber and thus experience the thermal conditions within the chamber. Conventionally, in order to cool the combustor cap, a large number of small effusion holes are provided in the plate allowing a cooling fluid to pass therethrough into the combustor chamber and cool the cap. This arrangement presents a number of challenges. First, the effusion holes in the cap may create stress risers within the cap due to the thermally induced stress. In other settings, a thermal barrier coating (TBC) may be applied to parts exposed to such heat to protect the parts from the thermally induced stresses. However, applying a TBC to a combustor cap including the smaller effusion holes is very hard and costly due to the need to not block the effusion holes. In addition, the effusion holes require the cooling fluid to enter the combustor chamber, which may negatively impact emissions of the combustion system.